Brown M S, Hallford D M, Galyean M L, Krehbiel C R, Duff G
Department of Animal and Range Sciences, New Mexico State University, Las Cruces 88003-0003, USA.
J Anim Sci. 1999 Nov;77(11):3068-76. doi: 10.2527/1999.77113068x.
Twelve 18-mo-old Debouillet ewes were used to determine the effect of ruminal glucose infusion on DMI, on urinary ammonium (NH4+) and urea N (UUN) concentrations, and on serum metabolite and hormone profiles. Ewes were limit-fed a 90% concentrate diet for 30 d, stratified by BW into three groups (average BW = 82.6+/-1.1 kg), and assigned randomly to receive 0, 5, or 10 g of glucose/kg of BW via esophageal intubation. Urine was collected hourly for 12 h and blood (jugular venipuncture) at 30-min intervals for 12 h. After 12 h, ewes were housed individually, allowed free access to the diet, and DMI was recorded for 5 d. Venous blood pH averaged 7.49, 7.48, and 7.48 at 0 h and decreased (linear [L], P < .01) at 12 h (7.41, 7.36, and 7.26) with increasing glucose. Serum glucose increased (L, P = .06) at 3 and 6 h. Serum L(+)-lactate increased (L, P = .08) at 3, 6, and 9 h, whereas serum D(-)-lactate increased linearly (P = .09) at 6 and 9 h and quadratically (P < .10) at 12 h. After the glucose challenge, DMI decreased (L, P < .05). Urinary pH and NH4+ were not influenced by glucose infusion; however, UUN increased at 3 (quadratic [Q], P < .05), 4, 5, 6 (L, P = .03), and 7 h (Q, P < .05) and decreased at 11 and 12 h (L, P = .09). As glucose infusion increased, serum creatinine increased at 9 (L, P < .01) and 12 h (Q, P = .02). Generally, serum Na and P increased (P = .09), whereas K decreased (P < .05), with glucose infusion. Lactate dehydrogenase activity increased with glucose infusion (Q, P < .10) at 3, 6, 9, and 12 h. Increasing glucose infusion increased serum globulin (Q, P = .06), albumin, and total protein (L, P = .08). Serum prolactin and vasopressin were not influenced (P = .22) by glucose infusion. Serum insulin and aldosterone increased quadratically (P = .08), whereas serum growth hormone decreased linearly (P = .08) as a result of increasing glucose infusion. Results suggest that UUN, serum insulin, aldosterone, and several serum constituents may serve as markers of organic acid load in ruminants fed high-concentrate diets.
选用12只18月龄的德布伊特母羊，以确定瘤胃输注葡萄糖对干物质采食量（DMI）、尿铵（NH4+）和尿素氮（UUN）浓度以及血清代谢物和激素谱的影响。母羊被限制饲喂90%精料日粮30天，根据体重分为三组（平均体重=82.6±1.1千克），并随机分配通过食管插管接受0、5或10克葡萄糖/千克体重。每小时收集尿液12小时，每隔30分钟采集血液（颈静脉穿刺）12小时。12小时后，将母羊单独饲养，自由采食日粮，并记录5天的DMI。静脉血pH在0小时时平均为7.49、7.48和7.48，随着葡萄糖输注量增加，在12小时时下降（线性[L]，P<.01）（分别为7.41、7.36和7.26）。血清葡萄糖在3小时和6小时时升高（L，P=.06）。血清L(+)-乳酸在3、6和9小时时升高（L，P=.08），而血清D(-)-乳酸在6小时和9小时时呈线性升高（P=.09），在12小时时呈二次方升高（P<.10）。葡萄糖挑战后，DMI下降（L，P<.05）。尿pH和NH4+不受葡萄糖输注影响；然而，UUN在3小时（二次方[Q]，P<.05）、4、5、6小时（L，P=.03）和7小时（Q，P<.05）升高，在11和12小时时下降（L，P=.09）。随着葡萄糖输注量增加，血清肌酐在9小时（L，P<.01）和12小时（Q，P=.02）时升高。一般来说，随着葡萄糖输注，血清钠和磷升高（P=.09），而钾下降（P<.05）。乳酸脱氢酶活性在3、6、9和12小时时随着葡萄糖输注而升高（Q，P<.10）。葡萄糖输注量增加会使血清球蛋白（Q，P=.06）、白蛋白和总蛋白升高（L，P=.08）。血清催乳素和血管加压素不受葡萄糖输注影响（P=.22）。随着葡萄糖输注量增加，血清胰岛素和醛固酮呈二次方升高（P=.08），而血清生长激素呈线性下降（P=.08）。结果表明，UUN、血清胰岛素、醛固酮和几种血清成分可能作为高精料日粮反刍动物有机酸负荷的标志物。
